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Issue No. 24, Article 3/November 5, 2004

Results from the Annual Fall Survey for Second-Generation European Corn Borers

With the help of University of Illinois Extension educators (IPM and Crop Systems), graduate students, and faculty and staff in the Department of Crop Sciences, we have completed the annual survey of second-generation European corn borers. We thank these individuals for helping us to keep our record of European corn borer populations intact from 1943 through 2004 (with the exception of 2 years during which the survey was not conducted). Without their gracious consent to help, such a time-consuming and labor-intensive task could not be completed.

In a break from tradition, we are not printing a table of averages of numbers of European corn borer larvae per 100 plants and percentage infestation in counties and crop reporting districts. Rather, we are providing a PowerPoint slide set that you can access from our IPM Web site. When you get to this page, look for Fall survey--2004 under "Related Links," and click. If you want to read about how the annual fall survey is conducted, click on "Fall survey," which is a fact sheet explaining the history and annual conduct of the survey.

The PowerPoint slides that you will access include the following for each crop reporting district in Illinois:

  • Average number of European corn borer (ECB) larvae per 100 plants for the counties surveyed within each crop reporting district
  • Average percentage infestation of ECB for the counties surveyed within each crop reporting district
  • Percentage infestation of ECB in 10 fields within one of the counties surveyed within the crop reporting district (prepared as an example of variability of infestation within a county)

On most of the slides, the averages for the crop reporting district (orange) and the state (red) are included. The slide set concludes with four slides that depict (1) the average number of ECB per 100 plants for all crop reporting districts and the state, (2) the average percentage infestation of ECB for all crop reporting districts and the state, (3) a map of Illinois depicting the average number of ECB per 100 plants in each of the counties surveyed, and (4) a map of Illinois depicting the average percentage infestation of ECB in each of the counties surveyed.

We invite you to use the information we have provided in this PowerPoint slide set. We ask only that you acknowledge the University of Illinois Department of Crop Sciences if you use the information in any of your educational meetings.

Overall, European corn borers in Illinois in 2004 were most noticeable through their relative absence. The average number of second-generation ECB per 100 plants in Illinois in 2004 was only 15.6, and the average percentage infestation was 17.1%. Many of the surveyors, upon turning in their information, inquired if anyone else was finding anything. For the most part, densities of ECB in 2004 were very low, as low as we have observed in many years. Remember, this does not necessarily mean that we won't experience economic infestations of ECB in 2005. Many factors affect survival (and mortality) of ECB, not the least of which are time of planting and weather conditions during moth flights. However, at this point, we know that the population of European corn borers that will overwinter is very low throughout most of the state.

If you have any questions about our results or use of the slides we have provided, please don't hesitate to contact us.--Kevin Steffey and Mike Gray

Authors:
Kevin Steffey
Mike Gray

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